Pension and Other Postretirement Benefits (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Compensation And Retirement Disclosure [Abstract]
Net periodic benefit cost	$ 14	$ 13	$ 41	$ 40